Charged particle beam writing method and charged particle beam writing apparatus

Abstract

A charged particle beam writing method includes acquiring the deviation amount of the deflection position per unit tracking deflection amount with respect to each tracking coefficient of a plurality of tracking coefficients having been set for adjusting the tracking amount to shift the deflection position of a charged particle beam on the writing target substrate in order to follow movement of the stage on which the writing target substrate is placed, extracting a tracking coefficient based on which the deviation amount of the deflection position per the unit tracking deflection amount is closest to zero among the plurality of tracking coefficients, and writing a pattern on the writing target substrate with the charged particle beam while performing tracking control in which the tracking amount has been adjusted using the tracking coefficient extracted.

What is claimed is: 
     
       1. A charged particle beam writing method comprising:
 acquiring a deviation amount of a deflection position per unit tracking deflection amount with respect to each tracking coefficient of a plurality of tracking coefficients having been set for adjusting a tracking amount to shift the deflection position of a charged particle beam on a writing target substrate in order to follow movement of a stage on which the writing target substrate is placed; 
 extracting a tracking coefficient based on which the deviation amount of the deflection position per the unit tracking deflection amount is closest to zero among the plurality of tracking coefficients; and 
 writing a pattern on the writing target substrate with the charged particle beam while performing tracking control in which the tracking amount has been adjusted using the tracking coefficient extracted. 
 
     
     
       2. The method according to  claim 1 , wherein the acquiring the deviation amount of the deflection position per the unit tracking deflection amount includes
 measuring, for the each tracking coefficient, the deviation amount of the deflection position with respect to at least one tracking amount while moving the stage in order to proceed writing in a first direction, and measuring the deviation amount of the deflection position with respect to at least one tracking amount while moving the stage in order to proceed writing in a second direction opposite to the first direction; and 
 calculating, for the each tracking coefficient, the deviation amount of the deflection position per the unit tracking deflection amount by using the deviation amount of the deflection position with respect to the at least one tracking amount measured in a case of moving the stage in order to proceed writing in the first direction, and the deviation amount of the deflection position with respect to the at least one tracking amount measured in a case of moving the stage in order to proceed writing in the second direction. 
 
     
     
       3. The method according to  claim 1 , further comprising:
 writing, with the charged particle beam, a plurality of figure patterns for which different tracking amounts are required, as evaluation patterns, on an evaluation substrate. 
 
     
     
       4. The method according to  claim 1 , further comprising:
 generating, using an existing tracking coefficient which has already been set in a writing apparatus, the plurality of tracking coefficients centering on the existing tracking coefficient. 
 
     
     
       5. The method according to  claim 2 , wherein the acquiring the deviation amount of the deflection position per the unit tracking deflection amount further includes
 fitting, for the each tracking coefficient, the deviation amount of the deflection position with respect to the at least one tracking amount measured in the case of moving the stage in order to proceed writing in the first direction, and the deviation amount of the deflection position with respect to the at least one tracking amount measured in the case of moving the stage in order to proceed writing in the second direction, wherein 
 the deviation amount of the deflection position per the unit tracking deflection amount is calculated as a gradient of a fitted approximation line, for the each tracking coefficient. 
 
     
     
       6. A charged particle beam writing apparatus comprising:
 a writing mechanism configured to include an emission source for emitting a charged particle beam, a stage for mounting a substrate thereon, and a deflector for deflecting the charged particle beam, and to write a pattern on the substrate with the charged particle beam while moving the stage and shifting a deflection position of the charged particle beam on the substrate to follow movement of the stage; 
 a deflection control circuit configured to control a tracking amount of the charged particle beam which is deflected by the deflector, using a tracking coefficient for adjusting the tracking amount to shift the deflection position of the charged particle beam on the substrate in order to follow the movement of the stage; 
 a tracking coefficient generation circuit configured to generate a plurality of tracking coefficients centering on a value of an existing tracking coefficient currently used by the deflection control circuit; and 
 an update circuit configured to update the existing tracking coefficient to a tracking coefficient based on which a deviation amount of the deflection position per unit tracking deflection amount is closest to zero among the plurality of tracking coefficients. 
 
     
     
       7. The apparatus according to  claim 6  further comprising:
 an acquisition circuit configured to acquire the tracking coefficient based on which the deviation amount of the deflection position per the unit tracking deflection amount is closest to zero among the plurality of tracking coefficients. 
 
     
     
       8. The apparatus according to  claim 6  further comprising:
 a fitting circuit configured to fit, for each tracking coefficient of the plurality of tracking coefficients, the deviation amount of the deflection position of the charged particle beam with respect to at least one tracking amount in a case of writing an evaluation pattern while moving the stage in order to proceed writing in a first direction, and the deviation amount of the deflection position of the charged particle beam with respect to at least one tracking amount in a case of writing the evaluation pattern while moving the stage in order to proceed writing in a second direction opposite to the first direction. 
 
     
     
       9. The apparatus according to  claim 8 , further comprising:
 a gradient calculation circuit configured to calculate, for the each tracking coefficient, a gradient of a fitted approximation line. 
 
     
     
       10. The apparatus according to  claim 9 , further comprising:
 an extraction circuit configured to extract the tracking coefficient based on which the gradient is closest to zero among the plurality of tracking coefficients.